1. Field of the Invention
The invention relates to a display technique, and more particularly, to an overcurrent protection circuit for a light source driving module and related backlight module.
2. Description of the Prior Art
In order to raise efficiencies in a LED backlight module, a high frequency switching mode converter is often used. Moreover, an overcurrent protection is often adopted in order to raise the stability. Conventionally, the overcurrent protection is realized by detecting whether a maximum current value exceeds a predetermined threshold, and if it exceeds the threshold, the high frequency switching mode converter generates a turning-off signal to perform the overcurrent protection. In this way, it prevents the power device of the LED backlight module from being working in a huge-current condition.
However, the above-mentioned overcurrent protection mechanism introduces some problems. For example, the threshold corresponds to a maximum current value. It means it is higher than a normal current value. Therefore, as long as the current value does not exceed the maximum value, the power device inside the LED backlight module continues to work. Unfortunately, when the current value is a little bit larger but not larger than the maximum current value, it may make the power of the power device larger than a rated power. This may cause the temperature of the power device higher than a normal temperature such that, the power device may be damaged or catch a fire.